It's not at all uncommon for Disney to shelve projects that have story issues. Beauty and the Beast was actually started back when Walt Disney was still alive but they couldn't find a way to make the story work, so the project was shelved - literally. Thankfully Disney does tend to go back to shelved projects later on to see if they can find a new way to make the story work. Considering we have Beauty and the Beast as an animated feature now, despite it being shelved decades ago, I think it highly likely that some time in the future you'll get to see The Snow Queen released.